/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package axil.framework.type;

import axil.api.AxilObject;
import axil.definition.UnitDefinition;
import axil.engine.Repository;
import axil.stdlib.numbers.type.Num;


/**
 * An abstract base class that does most of the work for a unitized type.
 */
public abstract class AbstractUnitizedType extends AbstractType
	implements UnitizedType {
	protected AbstractUnitizedType(String ident) {
		super(ident);
	}


	public UnitDefinition unit(String ident) {
		return Repository.instance().unit(ident);
	}


	/**
	 * Split the given string into two strings: the first containing the numeric
	 * value, and the second containing the units. A null value is returned
	 * if the splitting will not yield two non-empty strings.
	 */
	protected String[] split(String text) {
		final int size = text.length();
		for (int i = size - 1; i >= 0; i--) {
			char ch = text.charAt(i);
			if (! Character.isLetter(ch)) {
				String[] values = new String[2];
				if (ch == '-') {
					values[0] = text.substring(0, i);
					values[1] = text.substring(i + 1);
					return values;
				}
				values[0] = text.substring(0, i + 1);
				values[1] = text.substring(i + 1);
				return values;
			}
		}
		return null;
	}


	/**
	 * Parse the given text as a representation of the canonical form of this
	 * type. A null is returned if the text does not represent a valid object.
	 * The string given cannot be null.
	 */
	public AxilObject parse(String text) {
		String[] values = split(text);
		if (values != null) {
			Num n = Num.convert(values[0]);
			if (n != null) {
				UnitDefinition unit = unit(values[1]);
				if (unit != null) {
					return this.from(n, unit);
				}
			}
		}
		return null;
	}


	/**
	 * Transform the given native object into its equivalent value object. The
	 * object given is never null and is guaranteed to be one of the alias types
	 * indicated by this object's type (as reported by the type() method).
	 * If the object is one of the common types, then that indicator is also
	 * given.
	 */
	public AxilObject transform(Object object) {
		return null;
	}
}
